Clean Game Library

A complete development system for 2D games (arcade, side scrollers, platform games).
http://cleangl.sourceforge.net/

The Game of Life

Life: A CLEAN Programming Tutorial and Case Study
http://members.ozemail.com.au/~dekker/LIFE.HTML

Clean

The Software Technology Research Group develops this pure and lazy functional programming language. Description of the language and software downloads.
http://www.cs.ru.nl/~clean/

Sparkle

A semi-automated theorem prover for proving properties of Clean programs.
http://www.cs.ru.nl/Sparkle/